1. Field of the Invention
This invention relates to an electrical terminal connector for a receiving the threaded shaft of a slip fit stud connector of a transformer thereonto, the electrical terminal connector having at least two bearing surfaces for each size stud connector.
2. Prior Art Statement
It is known to provide only one thread in a substantially larger bore so different connectors are required for different studs. For instance, see U.S. Pat. No. 5,690,516 issued on 25 Nov. 1997 to David R. Fillinger. The simplicity leads to the primary drawback, different connectors for different stud diameters. A need exists for a multiple size slip fit connector to accommodate different size studs.
It is further known to provide threads on the same surface which provides only a line contact with either thread since the larger thread diameter is greater than a standard one inch stud. For instance, see the U.S. Pat. No. 7,320,626 B2 issued on 22 Jan. 2008, to Drane, et al., or the U.S. Pat. No. 6,939,183 B2 issued on 6 Sep. 2005, to Ferretti, et al. Drane, et al., and Ferretti, et al., only differ in the diameter of the stud hole in the connector. Since only line contact is established with any stud inserted into the stud hole, clamping by the set screws to hold the connector onto the stud would not provide sufficient holding force, especially for the smaller stud. Therefore, there is a need to establish multiple points of contact with the stud thread opposite the set screws to ensure proper holding force.
It is also known to provide a multiple sized transformer stud that has at least four threaded surfaces on at least two different thread diameters. Every thread is “bifurcated,” and therefore the stud touches the threads in two places opposite the set screws. For instance, see the U.S. Pat. No. 7,014,514 B2 issued on 21 Mar. 2006 to James L. Zahnen. The thread diameters do not exactly match the stud diameters so again there is only line contact with the stud even though the stud touches the threaded hole in two places. Since the threads do not match the stud threads, over tightening of the set screws is commonplace to ensure that full electrical contact is made between the stud and the connector threads. Often, this results in destruction of the stud connector through the sidewalls and the technician must replace the broken connector before finishing connections. Therefore, there is a need to exactly match thread contact with the stud threads opposite the set screws to ensure proper holding force without over tightening.
Additionally, it is known to provide three offset bores for a slip fit connector stud, one for the small stud thread, one for the large stud thread and a larger bore to provide for slip fitting the connector onto either stud. Full thread contact is provided on both studs at least for a portion of the periphery of the stud. For instance, see U.S. Pat. No. 6,579,131 B1 issued on 17 Jun. 2003 to Ashcraft, et al. Though significant contact is provided for both the large stud and the small stud commonly used for an electrical connector, manufacture of the stud connector is difficult and costly as five machining operations, three drilling operations on three different centers and two threading operations, are required to produce the slip fit connector. Accordingly, there is a great need for a slip fit connector that has fewer machining operations at greatly reduced cost.
Another known stud connector is provided with multiple bores, each having an exact thread which produce line contact on the larger thread at two points, ie where the smaller thread is provided into the larger bore. There remains full thread contact with the smaller stud in the smaller threaded hole. For instance, see the U.S. Patent Publication 2008/0188140A1 published on 7 Aug. 2008 by Hill, et al. As with Ashcraft, et al., considerable machining time is required to provide for the multiple bores and to define an exact thread in each bore. It is readily apparent, then, that a need still exists for a slip fit connector having multiple points of contact with any thread disposed therein.
Still further known is a stud connector that consists of a plurality of transverse ribs each with a centrally located semi-circular notch. For instance, see the U.S. Pat. No. 5,931,708 issued on 3 Aug. 1999 to Annas, et al. The transverse ribs are formed when the electrical connector is extruded and thus requires a separate collar to connect the stud to the electrical connector. The collar is slipped over the stud and then the stud connector assembled to the collar prior to tightening the screws. The separate parts are subject to loss as they are difficult to handle by a linesman on a pole wearing gloves. Thus, a need still exists for a slip fit stud connector that has multiple contacts with either size stud inserted therein.
Finally, it is also known to provide a stud connector that consists of a plurality of longitudinal ribs having apices at different locations from a center thereof. For instance, see the U.S. Pat. No. 7,338,333 B2 issued on 4 Mar. 2008 to Alexander Roy Norden. The longitudinal ribs are formed when the electrical connector is extruded and thus requires a separate cap nut to connect the stud to the electrical connector. The cap nut must held in place over the stud while slipping the stud into the hole between the cap nut and the longitudinal ribs prior to tightening the screws. As with Annas, et al., the separate parts are subject to loss as they are difficult to handle by a linesman on a pole wearing gloves. Thus, a need still exists for a slip fit stud connector that has multiple contacts with either size stud inserted therein.